1. Field of the Invention
The present invention relates to an optical pickup device, and more particularly, to an optical pickup device having a multitude of optical systems in a machine unit, the optical pickup device is applicable to an optical disk reproducing device for reproducing a multitude of optical disks.
2. Description of the Prior Art
In a general optical disk reproducing device for reproducing information recorded in a general information recording medium, a single optical disk driving mechanism is provided so that reproducing for a single optical disk is accomplished. In this optical disk, unit information is recorded on a multitude of tracks and larger amounts of information can be recorded in this kind of optical disk than in the conventional magnetic information recording medium using magnetic characteristics. By utilizing such characteristics of the optical disk, a program for exercising image songs, a movie program, etc. can be applied thereto and information having high quality sound and high resolution can be reproduced.
When the program for exercising the image songs is recorded on an optical disk having an information recording surface and when the information is required to be reproduced continuously, since the reproducing time of the optical disk having an information recording surface is limited, a multitude of optical disk reproducing devices and control units for controlling the operations of the optical disk reproducing devices should be separately provided. In such image song exercising system, during reproducing one optical disk in an optical disk reproducing device, another optical disk to be reproduced is assembled in another optical disk reproducing device. With completion of the reproduction of the first optical disk by the first optical disk reproducing device, the prepared optical disk reproducing device comes to be operated to reproduce the assembled second optical disk.
That is, for operating the image song exercising system continuously using the conventional optical reproducing device having one optical disk deck, at least two optical reproducing devices and at least two separate control units to control the optical reproducing devices are needed. This increases the manufacturing cost of the image song exercising system and occupying space.
Recently, an optical disk having both surfaces as information recording surfaces has been manufactured for recording at least two times the information than that in the optical disk having one information surface. However, an optical pickup device for reading information in the optical disk having two information recording surfaces, should be transported after completing the reproduction of the information recorded in one surface of the optical disk to reproduce the information recorded in the other surface of the optical disk. Accordingly, the mechanism of the transportation of the optical pickup device in the optical disk reproducing device for operating the optical disk having two information recording surfaces is comparatively complicated and the design thereof is not easy.
Recently, research on an optical disk reproducing device including mechanism for driving a multitude of optical disks in one device has attracted much interest. Further, a design for a pickup device which can operate a multitude of optical disks is largely required. For example, in U.S. Pat. No. 4,742,508 (issued to Lee et al.), a system which can selectively drive compact disk or video disk is disclosed. In this system, after reading the information recorded in one disk, the pickup device is transported to read information recorded in the other disk. However, this system also is complicated and continuous reading can not be accomplished due to the transportation of the pickup device.